Thermometer



' Sept. 25, 1 928.

E. B. FOOTE THERMOMETER Filed March 3, 1927 INVENTOR v ATTORNE? PatentedSept. 25, 1928.

umran STATES PATENT OFFICE.

EDWARD .B. FOOTE, OF ROCHESTER, NEW YORK, ASSIGNOR TO TAYLOR INMRUMIENTCOMPANIES, OF ROCHESTER, NEW YORK, A. CORPORATION OF NEW YORK.

' 'rnnnmomnrna.

Application filed Hatch 3, 1927. Serial No. 172,477.-

This invention relates to a thermometer specially adapted forco-operation with engines the operation of which entailsconsiderablevibratlon, such as steam turbines and internal combustionengines and more in particular Diesel en 'nes.

In order to o tain the best results with Diesel engines or engines ofsimilar character, it is practically necessary to watch the temperatureof .the products of combustion of each cylinder. On thesurface, theproblem is simple and requires merely the placing of .the temperatureresponsive part of a thermometricdevice into the exhaust of eachcylinder and indicating the heat reaction.

While it would seem that a large number of thermometric devices isavailable for that purpose, the practical application presents a problemwhich is not as simple as it might appear.

Most, if not all of the many constructions heretofore evolved andemployed for the measurement of temperatures of the order met with inDiesel engines, would not withstand the forces set up by the vibrationsso as to satisfy the requirements in that respect. It is the primary-andprincipal object of the invention to provide a thermometer which isadapted to successfully withstand the forces induced by vibrations andreacting upon the mechanism of the instrument. Another substantiallyconcurrent object is the provision of a thermometric instrument theaccuracy of which is not vitally affected by continuous vibrations.

For a full understanding of the invention, the principle of operation onwhich it is based and its distinctive features, reference is made to theaccompanying drawings in which Fi 1 isa front view of an instrumentembodym'g .the invention, parts being broken away to show certainimportant detall; and

Fig. 2 is a vertical section thereof.

In the drawings 1 is a casingof ordinary construction housing andsupporting the operating mechanism including primarily apressure-responsive motor element, a pointer or the like and mechanismfor translating motion from the motor element to the pointer.

In the particular instance, the motor element is a spring tube 2 of theBourdon type the inner end of which is attached to a stationary support3 which, as is usual, affords a connection etween the tube 2 and thecapillary tube 4. The outer or movable end of the 7 contact only at theextreme ends whereby the arm,

'dividuall bustion c ambers of a Diesel engine by means we tube 2 carries a depending arm 5 the free end of whlch 1s provided w th a pin 6-for co operation with the pointer 7.

e latter is mounted upon a shaft 8 which 1s supported in a bearing 9 onthe-casing 1. The (pr ncipal feature for which novelty is clalme 1s thetranslating mechanismjust broadly mentioned.

p The bearing 9 is preferably recessed between its ends so that theshaft 8 has bearingfrictional resistance is reduced to a practicalmln'imum; The shaft 8 has'convex end surfaces 8 and 8", one establishinga one point contact with the end surface 10 of the bearing 9 while theother end surface contacts with a block. 11 which is carried by a springbar 12 dlsposed to exert pressure upon the shaft 8 andtending to holdthe latter in contact witlf the bearing surface 10. While there isconsiderable latitude in respect to the applica-- mm of spring meansactlng axially upon the shaft 8, the use of a spring bar 12 is simpleand effective. It is supported at its ends upon suitable studs 13. i

The pointer 7 is not directly mounted upon shaft 8, but is secured-to arelatively stout a bar 14, which is mounted upon the. shaft 8. The pin 6and the bar 14 are of substantial size out of proportion to the 3 forcenecessary to move the pointer to provide a substantial wearing surface,and-are preferably made of materialshaving a high resistivity to wear. I

The bar 14 carries a pin or stud 15 to which is attached one end of atension spring 16 the other end of which is attached to the outer orfreeend of pin .6. This spring has the purpose to maintain the pin 6 andthe bar 14 in contact relation. The operation of the instrument is as"follows: Assume that the instrument described is one ofa series ofinstruments inconnected with the different comof the usual bulb filledwith an expansible fluid such as mercury. The degree of expansion of thefluid or the fluid pressure as measured by the pressure reaction uponthe Bourdon spring is then a criterion of the loe temperature-ofcombustion. This action ,is common to all instruments "of this type andis referred to merely for the sake of oompleteness. v I

Under the fluid pressure in the system oom- 0 take place between prisingthe bulb, the capillary and the Bour- Y nite clearance or unrestrainetion which could give riseto impact actions.- Moreover, what -wearthereEmay be or may the ends of shaft 8 and ploying gears,

tion of the 'due to sprin ments 'of .the prior art,

don spring, the latter expands causing the arm 5, which in effect is acrankarm, to move the bar 14 about the shaft 8 and with it the pointer7. I

The point of contact between the pin 6 and the bar 14 being maintaine bymeans of the spring 16, impact action between the contact surfaces isreduced to a minimum and practically to zero. distinction to all formsof instruments emlinks and levers interconnected by pivots etc, wherethe slightest'degree of clearance permitting relative moarts, no matterhowsmall such motion initially may be, gives rise to impacts the wearlngeffect of which is proportional to the distance of free motion i. e. the.clearance.

In positively interconnected parts such as mentioned it is practicallyimpossible to obtain fits which have no clearance. In fact, in delicateinstruments of the type described, perfect fits, aside from theexcessive labor and cost of producing them,

would introduce an excessive amount of friction which would render theinstrument either inoperative or at least useless from a practical pointof view.

By the arrangement described I have obtained 'a construction which hasthe equiva lent of a perfect fit in the sense that the-distance betweenthe interlinked parts is reduced to zero and which has a minimum offrictional resistance. The contact between the pin 6 and the block 14 isa line contact onl A 'l his applies ually and even more to the shaft '8which is old axially under pressure faces-8 an 8 serve to maintain theshaft in anormally centered. position while the.

spring bar 12 eliminates axial play. The spring bar 12 by its axialpressure tends to reventlateral motion of the shaft and in act.. suchmotion is practically eliminated. While the point contacts at the endsof the shaft Shave an insignificant resistance,-lateral motion and weararepractically eliminated because impact action is practicallyeliminated.

The train of translating mechanism thus has no posltive connectionreauiring a defirelative mothe'co-o rating surfaces or between pin 6 andthe ar 14, such wear can not cause any play or. increase of; play)--asin the instruut' is continuously taken up by the spring-action of springbar '12 or 16 neutralized.

I claim: 1 In aninstrument of thecharactendescr bed, the combinationwith a multiple- This is in contra-.

bar 12.. The small bearing surconnected to the convolution Bourdonspring, supported at its inner end, of a shaft, a crank bar securedthereto, a pointer carried by the crank bar, an arm secured to the outerend of the spring in a substantially radial direction, a pin extendingfrom the arm in a direction substantially parallel to the axis of thespring and the axis of the'shaft, the dispositlonof the parts'being suchthat the path of the pin. as

theresult of the movement of the spring intercepts the path of the crankarm, and spring means interconnecting the said arm and the crank bar forresilientl holding the latter and the pin in contact relation.

2. In an instrument scribed, the combination with a pressure-re sponsiveelement and a %ointer to be moved t ereby, of a shaft, a caringtherefor, a thrust hearing at one end of the shaft, spring.

therefor, a

of the character (IQ-I 'means for maintaining the shaft axially to claim2' in character demeans for maintaining the shaft axially under pressureagainst said thrust bearing 'bar mounted upon the shaftand carrying the4 pointer, an arm connected with the pressureresponsive element andmovable therewith, a'

pin on the arm, normally in contact with the j i said bar, and springmeans between the said arm and the said bar for maintaining the pin incontact with the latter.

5. In an instrument of the character des onsive element and a pointed tobe moved t ereby, ingtherefor, including a thrust earing at one end-ofthe shaft and spaced circumferential bearing portions, sprmg means formain- N5 taining the shaft axially under pressure against the thrustbearing, the pointer being shaft near the end op osite.

the thrust bearing and means connec with the pressure responsive elementfor actuating 120* the pointer. I I

. 6. In an instrument of the character described, the. co mbination witha pressure-'responsive element, of a relatively stout shaft ofarelatively stout shait, a bearscribed, the combination with apressure-recarrying at one-end a relatively stout crank "1 bar acomposite bearing for the shaft and includin as integral parts a thrustbearinaat the-en ar of the shaft.opposite the crank end and a peripheralbe'ari'n having bearing v contact with the shaft atpoints spaced from 1each other, spring means for maintaining the shaft axially underpressure against the thrust bearing, means connected with thepressure-responsive element for actuating the 5 crank bar and a pointercarried by the crank bar.

7 In an instrument of the character described, the combination wlth apressure-responsi e element and a pointer-to be moved a. thrust thereby,of a shaft, a bearing for supggting ring the shaft between its ends,

said thrust bearing, and means connected with the pressure-responsiveelement for angularly moving the shaft.

In testimony whereof I afiix my signature.

EDWARDB. FOOTE.

